Animalia Kingdom

Common features of Basic Animals Basic animals have several things in common, they have no backbone and no nerve cord.

Porifera Sponges, porous and able to live in groups called colonies for safety. Begin their lives motile and end their lives as adults that cannot move (Sessile). Hard exoskeleton Sponges (8,000 species) salt-water and reproduce asexually.

Cnidaria Jellyfish, these are motile their entire life, their skeleton is made of a thick jell-like material. They are some of the lower life aquatic animals found is fresh and salt water, (there are ,more than 15,000 species) Tentacles with stinging capabilities Reproduce by broadcast spawning.

Platyhelminthes Flatworms found in both salt and fresh water, their skeletons are made-up of a liquid material (more than 15,000 species) Basic and can reproduce by cloning or cutting in half, can regenerate.

Nematode Round worms and parasites there are more than 80,000 species known at this time. These compete with other organisms and take energy from them to live. Not true muscles. Skeletons made of liquid. Reproduce sexually, by broadcast spawning and can change sexes.

Rotifers Motile water invertebrates found in fresh water. 1,800 species known and they are the water worms, skeletons made of liquid and reproduce by broadcast spawning.

Mollusca Clams, Snails, Squid, Octopus, these organisms have a liquid skeleton and often an additional outside shell, or barrow a shell abandoned by another mollusca. They reproduce by broadcast spawning and are sexual. They all have a specialized mouth part like a beak. (110,000 species known.)

Earthworm

General terms Animalia (kingdom) Annelids (PHYLUM) – segmented worms. Earthworms and leeches are examples of these kinds of animals bilateral symmetry – organisms can be cut in to two similar halves serially – segmented body setae – external bristles used for traction when moving Segmentation is the division of the body of an organism into a series of similar parts.

Terms – where are you? Anatomy of the Earthworm Anterior – front (head) Posterior – tail (anus) Dorsal – back (top) Ventral – belly (bottom)

Animalia, Annelida, Oligochaeta, Lumbricidae, Lumbricus. terrestris

Skin Integument system – the skin is darker on the top (dorsal) than on the bottom (ventral) for camouflage and to protect the worm from predators. The skin is moist and plays an important role in allowing oxygen to pass through it to let the worm breathe. The skin also is divided into segments that help with movement. Each segment has two special “feet” called setae that are suction cup like and help hold the worm down as the muscles contract to pull it along the dirt. An enlarged segment called the clitellum that is used in reproduction. This houses the reproductive release openings where eggs and sperm are released.

Support and movement Skeletal system – hydro skeleton (endoskeleton) made of liquid material Muscle system - they have segments and move those segments with circular and elongated muscles that work together to pull and push the worm along. They also have suction cup like structures (setae) that hold them down in place two are found on each of the segments on the ventral side. Movement – motile, they can move by “eating their way” through the dirt.

Food Intake and outlet Digestive system – food enters the body by way of the mouth located on the anterior end of the earthworm then travels through the esophagus to the crop and gizzard to the intestine and then out the body by way of the anus. Food is broken down in the crop (grinding) and then further in the gizzard and in the intestine it is absorbed by cells that take the molecules to the needed parts of the body. Excretory system - Extra liquid is released through the skin to keep it moist and help in breathing. Liquid is important in the up-keep of the hydro skeleton for the worm. Solid wastes and unused dirt exits through the anus. What do they eat? The dirt, any nutrients that are in the dirt the worm takes out and uses. They do not know the difference in types of dirt, but they flourish in good soil.

Breathing taking in of oxygen Respiratory system – The earthworm breathes through its skin. The skin must be kept moist so that Oxygen can pass through it to the parts of the body that need it. This is a direct movement of oxygen (open system) Cells pick up the oxygen they need by an on demand process.

Sensing / reacting to the environment Nervous system – An earthworm can not see, smell, hear, or taste. They rely on their reaction to heat (feeling/ touch) to respond to their environment. They move to get away from extreme heat (seen to us as light) because they must keep their skin moist (wet) to breathe. If they dry out they will die. They do not have a brain, they have a mass of nerves often thought of as a brain, and they have a nerve cord that helps in the contraction of its muscles. They can not think you can not train them to do anything.

Making of new organisms Reproduction system - They are hermaphroditic organisms. This means they have both sexes. They are male and female. They have both sperm and eggs and release them to reproduce. They can NOT fertilize their own eggs, so they must swap sperm with another earthworm. Therefore they are sexual reproducers. The clitellum is where the openings for the eggs and sperm are located. On the ventral surface there are tracks that the sperm travel and then are taken into by the other worm. The eggs are then fertilized and released into the dirt in small sack like structures. The eggs are totally on their own during this time. The mother/father moves on and does not protect them in any way. The hatching time is usually about 15 days.

Blood and movement of material in the body Circulatory system – the earthworm really does not have “blood”, they have a fluid that makes up their hydro skeleton and this is where the oxygen and needed nutritional material is located. This is an open system; they have one major vessel on the ventral surface and one on the dorsal surface, but lack small ones to go to all cells. The oxygen is just absorbed by the cells that need it when they need it. Through the skin to the fluid to the cells.

Aortic Arch – earthworms do not have a heart, instead they have five aortic arches that help pump the liquid through-out the body of the worm. These arches can be easily torn or ripped, and by them selves can not pump the liquid the entire length of the body. Ganglion – mass of nerves that works to collect information for the nervous system